Ultrasonic Technology in Packaging Industry

Ultrasound is the propagation process of a mechanical vibration in a medium. Its frequency is generally above 20 kHz. Ultrasound is widely used, mainly in two categories, one is the use of weaker ultrasonic waves for various physical and chemical parameters, such as ultrasonic testing, ultrasonic leak detection, and ultrasonic ranging. The second is the use of high-intensity ultrasound to change the nature and state of substances, such as ultrasonic drilling, ultrasonic cleaning, ultrasonic welding, ultrasonic grinding, etc. Because of the high intensity and power of this ultrasonic wave, it is also called power ultrasound.

Our country has carried out research and application in all fields of ultrasound science and technology, and some projects have reached or reached the international advanced level. Ultrasonic technology not only has many miraculous effects, but also can realize automatic operation. It has a good application prospect in the packaging industry.

Ultrasonic drying

The ultrasonic drying method can increase the removal rate of moisture and reduce the content of final moisture. Compared with common heating and air drying methods, the advantages are that the drying speed is fast, the final moisture content is low, and the dried material is not destroyed. Will not be blown away by air flow. Therefore, ultrasonic drying has great potential for the dehydration of heat-sensitive materials such as Chinese medicine, food, wood products and paper products.

According to reports, Ukrainian Timber Processing Institute used ultrasonic energy to accelerate the polymerization of plywood. Tests have shown that it takes 10-15s if single side is affected by ultrasonic

The use of high-frequency electric heating requires 120-600s; if both sides use ultrasonic heating, the efficiency is 3-5 times faster than single-sided, and the quality of plywood is higher.

Corrugated paper drying is an important step in the production process of corrugated board. If ultrasonic drying method is used to replace the current electric heating drying method, the drying efficiency and the quality of corrugated board will be greatly improved, which has high application value and economic value.

Ultrasonic disinfection

At present, China's foodstuffs are mostly sterilized by high-temperature heating methods in the packaging process, but some foods are not easily subjected to high-temperature heat treatment. If any canned fruit is in the canning process, it will inevitably enter or remain some harmful bacteria in the canned food. After sealing, it is obvious that heating can no longer be performed. The best way is to penetrate ultrasound through the can into the food to kill the bacteria.

Ultrasonic cleaning

In the ultrasonic field, bubbles in the liquid are gradually generated and expanded, and then suddenly burst. In the process of rapid bubble collapse, high temperature and high pressure occur in the bubble, and a local strong shock wave is also formed in the liquid near the bubble. This is the so-called ultrasonic cavitation.

Due to cavitation, ultrasonic waves can “crush” and disperse dirt, such as fruits, mechanical parts, integrated circuit chips, and textiles, on the surface of objects present in liquid media. , play a role in cleaning the surface of the object. Ultrasonic cleaning has been widely used in the industry, its cleaning efficiency is high, the cleanliness is good, and it is especially advantageous for the cleaning of some objects with complex surface shapes.

In addition, ultrasonics can also be applied to crushing, filtering, dispersing, testing, etc., and have a wide range of application prospects in the packaging industry.